Optical super-sensitized silver halide emulsion

ABSTRACT

A SENSITIZED PHOTOGRAPHIC SILVER HALIDE EMULSION IS PREPARED BY INCORPORATING A DYE OF THE GENERAL FORMULA SET OUT BELOW AND A FORMALIN CONDENSATE INTO THE SILVER HALIDE EMULSION.   (-Y-N(-R1)-(CH=CH)N1-)&gt;C=(CH-C(-R2))N2-C&lt;(-CO-N(-R)-C(=CH-   C&lt;(-Y&#39;&#39;-N(+)(-R2)=(CH-CH)N3=))-Q-) (X(-))(N-1)   WHEREIN R1 AND R2 EACH REPRESENTS AN ALKYL GROUP, SUCH AS, A METHYL GROUP, AN ETHYL GROUP, B-HYDROXYETHYL GROUP, B-SULFOETHYL GROUP, A Y-SULFOPROPYL GROUP, A $-SULFOBUTYL GROUP, PROPYLSULFATE GROUP, ETC.; A CARBOXYALKYL GROUP OR A DERIVATIVE THEREOF, SUCH AS A CARBOXYMETHYL GROUP, A B-CARBOXYETHYL GROUP, A 2-(2-CARBOXYETHOXY) ETHYL GROUP, ETC.; A SULFOALKYL GROUP OR A DERIVATIVE THEREOF, SUCH AS A B-SULFOETHYL GROUP, A Y-SULFOPROPYL GROUP, A &amp;-SULFOBUTYL GROUP, A 2-HYDROXY-1-SULFOPROPYL GROUP, A 2-(3-SULFOPROPOXY)-ETHYL GROUP, A 2 - ACETOXY - 1 - SULFOPROPYL GROUP, 3 - METHOXY - 2 - (3 - SULFOPROPOXY)-PROPYL GROUP, 2 - (2 - (3 - SULFOPROPOXY)ETHOXY)ETHYL GROUP, 2-HYDROXY - 3 - (3&#39;&#39; - SULFOPROPOXY)PROPYL GROUP, ETC.; AN ALLYL GROUP; AN ARYL GROUP; A SUBSTITUTED ARYL GROUP; OR AN ARALKYL GROUP R REPRESENTS AN ALKYL GROUP OR AN ARYL GROUP, R3 REPRESENTS A HYDROGEN ATOM, AN ALKYL GROUP OR AN ALLYL GROUP, Y AND Y&#39;&#39; EACH REPRESENTS AN ATOMIC GROUP NECESSARY FOR FORMING A HETEROCYCLIC RING, Q REPRESENTS AN OXYGEN ATOM OR SULFUR ATOM, X REPRESENTS AN ANION, N IS 1 OR 2, SAID N BEING 1 WHEN THE DYE FORMS AN INTRAMOLECULAR SALT AND N1, N2 AND N3 EACH IS 0 OR 1.

United States Patent C) "ice Patented ,3: 2, 122

1 2 3,743,510 to a silver halide emulsion the light-sensitive wave length OPTICAL SUPER-SENSITIZED SILVER range of the silver halide emulsion is expanded and the HALIDE EMULSION silver halide emulsion is sensitized optically. Further, it

Yoshlyuki Nalfazawai s j M3520 sewaharai and is known that the extent of sensitization by the sensitizing N fi gh g fr fig g g 5 dye is influenced by the type of emulsion in which the Nesta; anfinaaoir.psiof intrastate; iiiiiiiiiiiii 605,952, 30, 1966 This application Sept 22, 1970 emulsion sensitized by a given sensitizlng dye can be 7 3 altered by varying the conditions in the emulsion. For Claims riorit application Japan,])ec, 30, 1965, example, the sensitivity is increased by the increase of 40/81,697 10 silver ion concentration, the reduction of hydrogen ion Int. Cl. G03c 1/10 concentration, or both. However, there is a drawback in 96-123 10 Claims thus sensitized emulsion in that the preservability of the emulsion is generally low.

Therefore, by adding a sensitizing dye together with ABSTRACT OF THE DISCLOSURE an additive into an emulsion, a dye sensitization is ob- A sensitized photographic silver halide e u s on is pr tained which is higher than the sum of each sensitization pared by lncorporating a dye of the gen ral formula 8613 obtained by individual addition. This phenomenon is out below and a Formalin condensate into the silver hacalled super-sensitization and the additive used for this lide emulsion. purpose is called a super sensitizing agent.

o /R "Y R2) o-N I R,-N -0H=0H)nc =cn- ,fli c=oH-d =on-o11 ,,=i1z,

(Kan-1 wherein R and R each represents an alkyl group, such as, a methyl group, an ethyl group, fi-hydroxyethyl group, SUMMARY OF THE INVENTION fl-sulfoethyl group, a -sulfopropyl group, a a-sulfobutyl The inventors have found that by incorporating in a group, propylsulfate group, etc.; a carboxyalkyl group or photographic silver halide emulsion the sensitizing dye a derivative thereof, such as a carboxymethyl group, a shown by general Formula I and a novola-k-type con- B-carboxyethyl group, a 2-(2-carboxyethoxy) ethyl group, densate of a substituted or an unsubstituted polyhydroxyetc.; a sulfoalkyl group or a derivative thereof, such as a benzene and Fonmalin, optical super sensitization can be p-sulfoethyl group, a 'y-sulfopropyl group, a fi-sulfobutyl obtained. The polyhydroxybenzene is one having from group, a 2-hydroxy-1-su1fopropyl group, a 2-(3-sulfo- 1 to 3 hydroxyl groups on the benzene nucleus. Further, propoxy)-ethy1 group, a 2 acetoxy 1 sulfopropyl the novolak-type condensate of a substituted or an ungroup, 3 methoxy 2 (3 sulfopropoxy)-propyl group, substituted polyhydroxybenzene and Formalin is herein- 2 (2 (3 sulfopropoxy)ethoxy)ethyl group, 2-hyvafter called simply Formalin condensate.

droxy 3 (3' sulfopropoxy)propyl group, etc.; an allyl 4o Objects of the present invention are thus: to provide group; an aryl group; a substituted aryl group; or an an optical supersensitized emulsion; to provide such a aralkyl group R represents an alkyl group or an aryl supersensitized combination where reduction of sensitivity group, R represents a hydrogen atom, an alkyl group or during storage is prevented; and where the formation of an allyl group, Y and Y each represents an atomic group fog is reduced.

necessary for forming a heterocyclic ring, Q represents an oxygen atom or sulfur atom, X represents an anion, n DETAILED DESCRIPTION OF THE PREFERRED is 1 or 2, said It being 1 when the dye forms an intra- EMBODIMENTS OF THE INVENTION molecular Salt and and each is 0 or The sensitizing dye of Formula I can be represented by the following general formula:

i) \C IF R I I(O =oH)M-o =GH-C ,Fh =oH-(=cH-orr ,,3=1 i-R,

( )n"-1 CROSS REFERENCES TO RELATED wherein R and R each represents an alkyl group, such APPLICATIONS as, a methyl group, an ethyl group, fl-hydroxyethyl group, fl-sulfobutyl group, a 2-hydroxy-1-sulfopropyl group, a Th1s application is a continuation-in-part of US. Ser. fate group, propylsulfate group, em; a carboxyalkyl group 605,952: filed 30i 1966: now abandonedor a derivative thereof, such as a carboxymethyl group, BACKGROUND OF THE INVENTION a fl-carboxvethyl p, a -(z-car oxy ethyl group, etc.; a sulfoalkyl group or a derivative thereof, such as a fi-sulfoethyl group, a 'y-sulfopropyl group, a The present invention relates to an improved opticalfi-sulfobutyl group, a 2-hydroxy-1-sulfopropyl group, a sensitized photographic silver halide emulsion and more 2 (3 sulf0propoXy)-ethyl group, a 2-acetoxy-1-sulfoparticularly to a so-called super optical sensitized silver propyl group, 3 methoxy 2 (3 sulfopropoxy)-propyl halide emulsion. group, 2 (2 (3 sulfopropoxy)ethoxy)ethyl group, 2-

hydroxy 3 (3' sulfopropoxy)propyl group, etc.; an

allyl group; an aryl group; a substituted aryl group; or It is well known in the field of producing photographic an aralkyl group. R represents an alkyl group or an aryl silver halide emulsions that by adding a sensitizing dye group, R represents a hydrogen atom, an alkyl group or Field of the invention Description of the prior art an allyl group, Q represents an oxygen atom or a sulfur atom, X represents an anion, n is 1 or 2, said It being 1 when the dye forms an intramolecular salt, an n 11 and n each is or 1.

Y and Y each represents an atomic group necessary for forming a heterocyclic ring. Y and Y may, for example, represent the atomic group necessary to complete a heterocyclic ring of the pyridines series (e.g. 2-pyr1dme, 2-pyridine), the tetrazole series (e.g. tetrazole, 4-methyltetrazole, 4-ethyltetrazole), the thiazole series (e.g. thrazole, 4-methylthiazole, 4-phenylthiazole, S-methylthiazole, S-phenylthiazole, 4,5-dimethylthiazole, 4,5-diphenylthiazole, 4-(2-thienyl)-thiazole), the benzothiazole series (e.g. benzothiazole, 4-chlorobenzothiazole, S-chlorobenzothiazole, 6 chlorobenzothiazole, 7 chlorobenzothiazole, S-methylbenzothiazole, G-methylbenzothiazole, bromo benzothiazole, S-phenylbenzothiazole, S-rnethoxybenzothiazole, 6-methoxybenzothiazole, S-ethoxybenzothiazole, 5, 6 dimeth'oxybenzothiazole, S-hydroxybenzothiazole, 6- hydroxybenzothiazole), the naphtho[1,2]thiazole series, the naphtho[2,3]thiazole series, the naphtho[2,1]thiazole series, the oxazole series (e.g. oxazole, 4-methyloxazole, 5- methyloxazole, 4-phenyloxazole, 4,5-diphenyloxazole, 4- ethyloxazole, 4,5-dimethyloxazole, S-phenyloxazole), the benzoxazole series (e.g. benzoxazole, 5-chlorobenzoxazole, S-methylbenzoxazole, S-phenylbenzoxazole, 6-meth ylbenzoxazole, 5,6 dimethylbenzoxazole, '5 methoxybenzoxazole, S-ethoxybenzoxazole, S-hydroxybenzoxazole, 6-hydroxybenzoxazole), the naphtho[1,2]oxazole series, the naphtho[2,3]oxazole series, the naphtho[2,1]oxazole series, the selenazole series (e.g. 4 methylselenazole, 4- phenylselenazole, th'e benzselenazole series e.g. benzselenazole, 5-chlorobenzselenazole, S-methylbenzselenazole, S-methoxybenzselenazole, 5 hydroxybenzselenazole, 5- phenylbenzselenazole), the naphthol[l,2] selenazole series, the naphtho[2,l]selenazole series, the thiazoline series (e.g. thiazoline, 4-1nethylthiazoline), the oxazolino series (e.g. oxazoline), the quinoline series such as the Z-quinoline series (e.g. 2-quinoline, 3-methyl-2-quinoline, 5-methyl-2- quinoline, 8-methyl-2-quinoline, 6-methyl 2 quinoline, 6-chloro-2-quinoline, 6-methoxy-2-quinoline, 6-ethoxy-2- quinoline, 6-hydroxy-2-quinoline, 8-hydroxy-2-quinoline) and the 4-quinoline series (e.g. 4-quinoline, 6-methoxy-4- quinoline, 8-methyl-4-quinoline, 6-chloro-4-quinoline, 8- chloro-4-quinoline, 6-fiuoro-4-quinoline, 8 fiuoro 4- quinoline, 6-hydroXy-4-quinoline, 8-hydroxy-4-quinoline, 6-methyl-4-quinoline, the l-isoquinoline series (e.g. l-isoquinoline, 4-dihydro-1-isoquinoline), the 3-isoquinoline (e.g. 3-isoquinoline), the benzimidazole series (e.g. 1,3- diethylbenzimidazole, 1,3-diethyl-S-chlorobenzimidazole, 1,3-diethyl 5, 6 dichlorobenzimidazole, 1-ethyl-3phenylbenzimidazole, the 3,3'-dialkylindolenine series (e.g. 3,3-dimethylindolenine, 3,3',5-trimethylindolenine, 3,3',7- trimethylindolenine) etc.

The substituted or unsubstituted polyhydroxybenzene used in the present invention is shown by the following general formula:

wherein R and R each represents OH, OM, 0R NH S N(R6)2, NZHNH or -NHNHR (where R Presents an alkyl group having 1-8 carbon atoms, an allyl Hp or an :aralkyl group and M represents an alkali metal or an alkaline earth metal), and I1 and n each represents an integer of from 1 to 3, inclusive. Typical ples of poly hydtnoxybenzenes shown by the above formulas are p-dic xytlirenzene, o-dioxybenzene p-hydroxybenzoic acid, p-hy, hmxybemne sulfonic acid, o-hydroxy benzoic acid, O-lrydv rpxybsnzem sulfonic acid, m-hydroxy benzoic acid, m-hydroxybenzene sulfonic acid, a-resorcinic acid, fl-resorcinic acid, 'y-resorcinic acid, 3,5-dihydroxybenzene sulfonic acid, 2,4 dihydroxybenzene sulfonic acid, 2,6-dihydroxybenzene sulfonic acid, 2,5-dihydroxy benzoic acid, 2,5-dihydroxy benzoic acid, 2,5-dihydroxybenzene sulfonic acid, pyrogallol carboxylic acid (5) (gallic acid), pyrogallol carboxylic acid (4), pyrogallol sulfonic acid (5), pyrogallol sulfonic acid (4) and their alkali metal salts (Li, Na, K, etc.) and their alkaline earth metal salts (Mg, Ca, etc.). Furthermore, effectively employed in the present invention are the amides or hydrazides of the above mentioned carboxylic acids or sulfonic acids and the alkyl( 1-8 carbon atoms)-, aralkylor allyl-derivatives of their amides or hydrazides. The esters of the above-mentioned carboxylic acids and the sulfonic acids can also be etfectively used in this invention.

The condensate of the above-mentioned substituted or unsubstituted polyhydroxybenzene and formaldehyde may be prepared by a conventional novolak-type method for producing a phenol-formaldehyde resin. For example, it may be prepared generally as follows: The poly-substituted hydroxybenzene is dispersed in water, and after the addition of concentrated hydrochloric acid and 37% Formalin, the dispersion is stirred for 30 to minutes at 100 C. Thereafter, if necessary, hydrochloric acid is supplemented followed by continuation of heating and stirring. After the reaction is finished, the product is poured into cold water and the thus precipitated product is collected and purified to provide the condensate. Other eX- amples will :be described more in detail. For example, 415 parts of p-hydroxy benzoic acid is dispersed in 1000 parts of water with stirring vigorously and to the dispersion are added 25 parts of concentrated hydrochloric acid and 245 parts of 37% Formalin. Then the reaction mixture is stirred for 30 minutes at 100 C. and, after the addition of 20 parts of concentrated hydrochloric acid, the system is reacted for an additional 30 minutes. At the end of the reaction, 20 parts of concentrated hydrochloric acid is added to the reaction product and the system is stirred, whereby the reaction solution becomes turbid and white. After stirring for about minutes, the stirring is stopped and the reaction mixture is poured in 3000 parts of cold water with stirring. The thus precipitated product is recovered by filtration, re-dissolved in 1000 parts of methanol while the product is in a semi-dried state, and then recrystallized with water. The product is recovered by filtration and dried to provide the objective condensate. In the case employing other substituted or unsubstituted polyhydroxybenzenes, the above-mentioned method or slightly modified methods can be applied. The condensate obtained by the above-mentioned methods has about 2-10 units in a condensation unit (degree of polymerization) as is general with novolak resins.

A condensate having 2-10 units, in degree of polymerization, is effective in the present invention, but a condensate having from 2-5 units in degree of polymerization, or having a molecular weight of from about 300 to 800 is particularly desirable.

When the Formalin condensate of the present invention is added to a silver halide emulsion containing sensitizing dye (I), a very excellent super-sensitization can be obtained without lowering the sensitivity. I

Some of sensitizing dyes (I) have such drawbacks that when they are incorporated in photographic light-sensitive materials, the sensitivity thereof is lowered during storage, but by incorporating the dye together with the Formalin condensate in accordance with the present invention, the reduction in sensitivity during storage can be remarkably prevented. Moreover, the formation of fog in the emulsion caused by the presence of sensitivity dye (I) can be reduced by the addition of the Formalin condensate to an emulsion containing the sensitizing dye (I).

It is preferable that the concentration of the sensitizing dye (I) in silver halide emulsion be 0.002-02 g./gram molecule of silver halide and the concentration of the Formalin condensate in said emulsion be 0.1-2.0 g./ gram molecule of silver halide. Furthermore, a particularly effective concentration ratio of the sensitizing dye (I) to the Formalin condensate is from 1:5 to 1:500. The sensitizing dye (I) may be added to the emulsion by any method widely known in the field. The Formalin condensate may be incorporated in the emulsion as a solution thereof in water or an organic solvent such as methanol or ethanol. It is convenient to incorporate the sensitizing dye (1) and the Formalin condensate into the emulsion directly before coating.

The sensitizing dye (I) may be added to the emulsion before or after the addition of the Formalin condensate, or a mixture of the sensitizing dye (I) and the Formalin condensate may be added to the emulsion. They may also :be added to the emulsion after water-washing and during ripening.

In the present invention, usual gelatino silver halide emulsions are generally employed, but materials other than gelatin having no bad influences on the photographic light-sensitive materials, such as resinous materials or cellulose derivatives, may be used.

The silver halide used in the emulsion of this invention may be silver chloride, silver bromide, silver bromo-iodide, silver bromo-chloride, silver bromo-chlorodide, and the like. The silver halide emulsion used in this invention may also contain the usual additives, such as chemical sensitizing, hardening agents, antifoggants, wetting agents, stabilizers, plasticizers, development promoters, an antibronzing agent, couplers, fluorescent whitening agents, anti-air foggants, and the like. The silver halide emulsion of this invention may be applied by conventional methods to a suitable support, such as, a glass plate, a cellulose derivative film, a synthetic resin film or a 'baryta paper.

The present invention will be explained practically by the following examples:

EXAMPLES Into a silver halide emulsion there was added (1) only the sensitizing dye shown by the general Formula I, or (2) the sensitizing dye shown by the general Formula I and the Formalin condensate, and the resulting emulsion was applied to a cellulose acetate base. If the pH was lowered by the addition of the Formalin condensate in the emulsion, the pH was adjusted by the addition of an alkali. After drying, the thus coated film was exposed through a Fuji No. 7 filter (made by Fuji Photo Film Co., and transmitting light having a wave length longer than 590 millimicrons) and then developed. The sensitivity and fogs of the thus developed film were measured. The results of the measurements are shown in Table 1. In the table, the sensitivity is shown by M.U.D. (the reciprocal of exposure necessary for giving fog +0.1 in optical density), the sensitivity in the case of incorporating only the sensitizing dye in the emulsion is defined to be 100, and the sensitivity in the case of incorporating the novolaktype condensate together with the sensitizing dye in the emulsion is shown by comparison with the defined sensitivity.

In the case of incorporating only the condensate of the substituted or unsubstituted polyhydroxybenzene and formaldehyde in the emulsion, it gave no sensitizing action to the emulsion or very low sensitizing action, if any. The emulsions used in the comparative formulae were from the same batch, but, in other examples, various emulsions from different batches were used. In Table 1, a silverbromo-iodide emulsion was used in Examples 1-10; while the emulsion from the same batch was used in Examples 1-8 and emulsions from different batches were used in Example 9 and Example 10. Furthermore, the photographic light-sensitive elements prepared in Examples 1-8 and Examples 11-13 were developed for 6 minutes at 20 C. in a developer having the composition shown in Table 2, and those prepared in Formulae 9-10 were developed for minutes at 20 C., in a developer having the composition shown in Table 3. Further, it should be understood that the sensitizing dyes and the Formalin condensates used in the present invention should not be limited to the following formulae shown in Table 1.

TABLE 1 Sensitivity Additive (mg/molecular g. of silver halide) 1(a) 5-[(l-ethyl-t-quinolylidenc)-ethylidene]- 3-allyl-2-((1 ethyl-Z-quinolynyl perchlorate)-rnethylene)-4-thiazo1idinone (12).

(b) (a) (12) plus 'y-resorcinic acid-formaldehyde condensate (2,000).

2(c) 5-((1-ethyl-2-quinoly1idene)-ethylidene)-3- ethyl-2-((4-quinolynylethiodide)ethylene) 4-tl1iazolidinone (10).

(d) (c) (10) plus condensate of 3,5-dihydroxy benzoic acid hydrazide and formaldehyde 3(e) 5-((1-ethyl-2-qu.inolylidene)-ethylidene)- 3-allyl-2-((6,7-benzo-2-benzothiazolylethiodide)-methylene)-4-thiazolidinone 7(m) 5-[(ethyl-4,5-benzo-2-benzothiazolylidene)- ethylidene)-3-ethyl-2-[(4-quinolinylethiodide)methyleneH-thiazolidinone(14).

(n) (m) (14) plus condensate of galhc acid and formaldehyde (3,000).

8(0) Anhydro-5-((3-ethyl-4,5-benzo-2-benzothiazolylidene)-a-phenylethylidene)-3-ethyl- 2-((3- -sulfopropyl-4,5-diphenyl-2-thiazo lyl tlshydroxidwmethylene)-4-thiazolidinone 5). (p) (o) plus condensate of p-hydroxybenzene sulfonic acid amide and formaldehyde (700).

9(0) 5-((l-ethyl-4-quinolylidene)-ethylldene)- 3-allyl-2-((5,6 dimethyl-2-benzoxazolylcthiodide)methylene)-4-thiazolidinone (9).

(r) (q) (9) plus condensate of 'y-resorcinic acid and formaldehyde (4,000).

(t) q) (18) plus condensate of p-hydroxy benzoic acid and formaldehyde.

11 (u) 5-( (1-ethy1-4-quinolylidene) -ethy1idene) 3-allyl-2-((3-ethyl-4.5-diphenyl-2-thiazolyl perchlorate)methylene)-4-thiazolidinone (v)- (u) (50) plus condensate of fl-resorciuic acid and formaldehyde (5,400).

(w) (u) (50) plus condensate of p-hydroxy benzoic acid and formaldehyde (2,700).

12(x) Anhydro-5-((1-ethyl-4-quinolylidene)- ethylidene)-3-allyl-2-((3-v-sulfopropyl- 4,5-diphenyl-Z-thiazolylhydroxide)- methylene)-4-thiazolidinone (38).

(y) (w) (38) plus condensate of p-dioxybenzene and. formaldehyde (11,000).

(z)..- (w) (38) plus condensate of methyl ester of 'y-resorcinic acid and formaldehyde (5,500).

13(a) 5-( (1-ethyl-4-quinolylidene) -ethyhdene) 3-ethy1-2-(3-ethy1-2-benZoxaZ0lyl perchlorate)methylene)-4-oxazolidinoue (8).

(b) (Z) (8) plus condensate of m-hydroxy benzoic acid and formaldehyde (2,000).

Fog

TABLE 2 G. N-methyl-p-aminophenol sulfate 2.0 Hydroquinone 4.0 Sodium sulfite 40 Sodium carbonate (anhydrous) 24 Potassium bromide 1 Water to make 1 liter.

TABLE 3 G. N-methyl-p-aminophenol sulfate 2.0 Hydroquinone 5.0 Sodium sulfite 100 Borax 2 Water to make 1 liter.

The preparation of the sensitizing dyes (I) used in the present invention will be described with reference to several examples:

(1) Preparation of -((1-ethyl-2-quinolylidene)ethylidene) 3 ethyl-2-((4-quinolynylethiodide)methylene)-4- thiazolidinone:

A mixture of 1 g. of 3-allyl-5-(1 ethyl 4 quinolylidene)ethylidene)rhodanine and 1 ml. of diethyl sulfate was heated for 1 hour to 120 C. The reaction product was mixed with 2 g. of anhydro-2-methyl-3-(3-sulfopropyl)-6,7-benzo-benzothiazolium hydroxide and ml. of pyridine and the mixture was boiled for 30 minutes under refluxing.

After cooling, the thus produced dye was filtered under suction, washed with ethyl acetate, water and methanol, and recrystallized from a methanol-chloroform solvent (1:2). The melting point of the thus obtained product was 280 C. (accompanied by decomposition).

(3) Preparation of 5-((1-ethyl-4-quinolylidene)ethylidene) 3 allyl-2-((1-ethyl 2 quinolynyl perchlorate) methylene) -4thiazolidinone A mixture of 0.5 g. of 3-a1lyl-5-((1-ethyl-4-quinolylidene)ethylidene)rhodanine and 0.5 ml. of diethyl sulfate was heated for 1 hour at 120 C. The reaction product was mixed with 0.6 g. of l-ethyl-Z-methylquinolinium iodide and 5 ml. of pyridine and the mixture was boiled for 30 minutes under refluxing. The product was precipitated by the addition of 5 ml. of an aqueous 20% solution of sodium perchlorate. The precipitate was filtered under suction, and washed with water, and recrystallized from methanol. The melting point of the dye was 251 C. (accompanied with decomposition).

(4) Preparation of 5-((1-ethyl-4-quinolylidene)ethylidene)-3-allyl-2-( (6,7 benzo-2-benzothiazolyl ethiodide) methylene-4-thiazolidinone:

A mixture of 0.5 g. of 3-allyl-5-((1-ethyl-4-quinolylidene)ethylidene)rhodanine and 0.5 ml. of diethyl sulfate was heated for 1 hour to C. The reaction product was mixed with 0.6 g. of 1-ethyl-2-methyl-6,7-benzo-benzothiazolium-p-toluene sulfonate and 5 ml. of pyridine was boiled for 30 minutes under refluxing. The product was precipitated by the addition of an aqueous 20% solution of potassium iodide and the precipitate was filtered under suction and washed with water. The thus obtained crude dye was recrystallized from methanol. The melting point of the dye was 258-259 C. (accompanied by decomposition).

Other sensitizing dyes used in this invention may be prepared by processes similar to the above-mentioned processes. The melting points of the sensitizing dyes used in the examples of this invention are shown in Table 4.

In Table 5, a silver bromo-iodide emulsion was used in Examples 14-23, while a silver chlorobromide emulsion was used in Examples 15-45. The film was exposed through a Fuji -No. 3 filter [trademark] (made by Fuji Photo Film Co., and transmitting light having a wave length longer than 500 millimicrons) and then developed. The materials of Ex. 14-23 were developed for 10 minutes at 20 C. using the composition of Table 3, and Ex. 24-45 for six minutes at 20 C. using the composition of Table 2.

TABLE 5 Mg./gram mol of silver halide Example Sensi- No. Dye Formalin condensate tivity Fog 14(a) Dye 14(80) None 100 0. 05 (b) do Condensate of o-hydroxy- 181 0.05

benzoic acid and formaldehyde (3,000). 15(e) Dye 1507).. None 100 0.05 (d) do Condensate 0f o-hydroxy- 167 0.05

benzoic acid and formaldehyde (3,000). 16(e) Dye 16(77). None 100 0.05 (f) do Condensate of o-hydroxy- 132 0.05

benzoic acid and formaldehyde (3,000). 17 (g) Dye 17(81),. None 100 0.05 (h) do Condensate of o-hydroxy- 170 0. 05

benzoic acid and formaldehyde (3,000). 18( Dye 18(77) None 100 0.05 (J) do Condensate of o-hydroxy- 135 0.05

benzoic acid and formaldehyde (3,000).

(1) Preparation of dye =OH-OHS 0 S /S S E o N -crt 15 0=GH--CH=O 2H; CH3 \N/ 6 C=CHC\ i H b/ I 2 E z s l Hi I a CZHB CzHs A mixture of 1 g. of 3 ethyl 5 {[3 ethyl 2 (6,7- benzothiazolidene)]ethylidene}rhodanine and 1.2 ml. of N o diethyl sulfate was heated for 1 hour at 120 C. The re- I- N action product was mixed with 1.2 g. of 3-ethyl-4,5-di- L N/ phenyl-2-methylthiazolium iodide and 7 ml. of pyridine 6 and the mixture was boiled for 1 hour under refluxing.

After cooling, the dye separated from the solution was collected on the filter under suction, washed with acetone and then recrystallized from methanol. The melting point of the product was 266 C. (accompanied by decomposition).

1130\ I (2) Preparation of dye 27 mo \13 I lNJ s\ i; =oH-oHs CZHE (1H 2 N 0 OH I p I? III A mixture of 1 g. of 3-ethyl-5-[(3-ethyl-2-benzothiazolidene)ethylidene]rhodanine and 1 ml. of diethylsulfate was heated for 1 hour at 120 C. The reaction S product was mixed with 1.3 g. of 1-ethylquinoldinium CH O l iodide and 6 ml. of pyridine and the mixture was boiled I H O N CH l After cooling, the dye separated from the solution was 2 5 N filtered under suction, washed with acetone and recrystal- 02H; lized two times from methanol. The melting point of the 2 5 product was 256.5 C. (accompanied by decomposition).

S O S =CHCH S O HaC-- H C s N o N CH- 3 Ol J:CH z u (1: I 3/ for 1 hour under reflux.

(3) Preparation of dye 32 A mixture of 1.5 g. of 3-methyl-5-[(3-ethyl-2-benzothiazolylidene) ethylidene] rhodaniue and 2 ml. of diethylsulfate was heated for 1 hour at 120 C. The reaction 0 product was mixed with 1.5 g. of l,2,3,3-tetramethyl- I 0 7 0 indolenium iodide and 6 ml. of pyridine and the mixture Hag :l J Was boiled for 30 minutes under reflux. After cooling, N 0 the product separatedfrom the solution was collected on (32115 0104. \N \i H3 the filter under suction, washed with acetone and recrystallized from pyridine. The melting point of the product @2115 was 274.5 C. (accompanied by decomposition).

(4) Preparation of dye 33 A mixture of 1.5 g. of 3-methyl-5-[(3-ethyl-2-benzothiazolylidene)ethylidene] rhodanine and 2 ml. of ethylsulfate was heated for 1 hour at 120 C. The reaction production was mixed with 1.5 g. of 3-ethyl-2-methylbenzoxazolium iodide and 6 ml. of pyridine and the mixture was boiled for 3 hours under reflux. After cooling, the product separated from the solution was filtered under suction, washed with acetone and recrystallized from pyridine. The melting point of the product was 275.5 C. (accompanied by decomposition).

Other sensitizing dyes used in this invention may be prepared by process similar to the above-mentioned process and/or the process set forth in US. Pat. No. 2,947,630.

While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the in- Vention.

What is claimed is:

1. A photographic silver halide emulsion containing (1) at least one sensitizing dye (I) selected from those represented by the following general formula:

wherein R and R each is a member selected from the group consisting of an alkyl group, a substituted alkyl group selected from the group consisting of a hydroxyalkyl group, an acetoxyalkyl group, an alkylsulfate group, a carboxyalkyl group, a carboxyalkoxyalkyl group, a sulfoalkyl group, a hydroxysulfoalkyl group, a sulfoalkoxyalkyl group, an acetoxysulfoalkyl group, an alkoxysulfoalkoxyalkyl group, a sulfoalkoxyalkoxyalkyl group, and a hydroxysulfoalkoxyalkyl group, an allyl group, an aryl group, and an aralkyl group; R is a member selected from the group consisting of an alkyl group and an allyl group; R is a member selected from the group consisting of a hydrogen atom, an alkyl group and an aryl group; Y and Y each is an atomic group necessary for forming a heterocyclic ring selected from the group consisting of the pyridine series, the tetrazole series, the thiazole series, the benzothiazole series, the naphtho [1,2]thiazole series, the naphtho [2,3]thiazole series, the naphtho [2,l]thiazole series, the oxazole series, the benzoxazole series, the naphtho [1,2]oxazole series, the naphtho [2,3]oxazole series, the naphtho [2,1]oxazole series, the selenazole series, the benzselenazole series, the naphtho [l,2]selenazole series, the naphtho [2,1]selenazole series, the thiazoline series, the oxazoline series, the quinoline series, the l-isoquinoline series, the 3-isoquinoline series, the benzimidazole series, and the 3,3-dialkylindolenine series; Q is a member selected from the group consisting of an oxygen atom and a sulfur atom; X is an anion; n 11 and n each is or 1;

1 6 and n is 1 or 2, said n being 1 when the dye forms an intramolecular salt, and (2) at least one condensate of formaldehyde and a member selected from the group consisting of polyhydroxybenzenes of the formulae 4) OH COR; S 2R5 wherein R and R each is a member selected from the group consisting of OH, OM, 0R NH NHR N(R NHNH and --NHNHR where R represents a member selected from the group consisting of an alkyl group having from 1 to 8 carbon atoms, an allyl group, and an aralkyl group, and M is a member selected from the group consisting of an alkali metal and an alkaline earth metal; and n; and m each is an integer of from 1 to 3 inclusive.

2. The photographic silver halide emulsion as claimed in claim 1 wherein the degree of polymerization of the condensate is from 2 to 10 units.

3. The photographic silver halide emulsion as claimed in claim 1 wherein the degree of polymerization of the condensate is from 2 to 5 units.

4. The photographic silver halide emulsion as claimed in claim 1 wherein the concentration of said sensitizing dye in said silver halide emulsion is from 0.002 to 0.2 gram per gram molecule of silver halide and the concentration of said condensate is from 0.1 to 2.0 grams per gram molecule of silver halide.

5. The photographic silver halide emulsion as claimed in claim 1 wherein the concentration ratio of said sensitizing dye to said condensate in the silver halide emulsion is from 1:5 to 1:500.

6. A photographic light-sensitive element comprising a support bearing at least one silver halide emulsion containing (l) a sensitizing dye selected from those represented by the following general formula:

wherein R and R each is a member selected from the group consisting of an alkyl group, substituted alkyl group selected from the group consisting of a hydroxyalkyl group, an acetoxyalkyl group, an alkylsulfate group, a carboxyalkyl group, a carboxyalkoxyalkyl group, a sulfoalkyl group, a hydroxysulfoalkyl group, a sulfoalkoxyalkyl group, an acetoxysulfoal-kyl group, an alkoxysulfoalkoxyalkyl group, a sulfoalkoxyalkoxyalkyl group, and a hydroxysulfoalkoxyalkyl group, an allyl group, an aryl group, and an aralkyl group; R is a member selected from the group consisting of an alkyl group and an allyl group; R is a member selected from the group consisting of a hydrogen atom, an alkyl group and an aryl group; Y and Y' each is an atomic group necessary for forming a heterocyclic ring selected from the group consisting of the tetrazole series, the thiazole series, the benzothiazole series, the naphtho[l,2]thiazole series, the naphth0[2,3]thiazole series, the naphtho[2,l] thiazole series, the oxazole series, the benzoxazole series, the naphtho[l,2]oxazole series, the naphtho [2,3]oxazole series, the naphtho[2,1]oxa'" the selenazole series, the benzselenazole series, the naphtho[1,2]selenazole series, the naphtho[2,1] selenazole series, the thiazoline series, the oxazoline series, the quinoline series, the l-isoquinoline series, the 3-isoquino1ine series, the benzimidazole series, and the 3,3'-dialkylindolenine series; Q is a member selected from the group consisting of an oxygen atom and a sulfur atom; X is an anion; n 11 and 12 each is 0 or 1; and n is 1 or 2, said n being 1 when the dye forms an intramolecular salt, and

(2) a condensate of formaldehyde and a member selected from the group consisting of polyhydroxybenzenes of the formulae and | JJORA SO R 18 selected from the group consisting of an alkali metal and an alkaline earth metal, and 11 and n each is an integer of from 1 to 3 inclusive. 7. The element as claimed in claim 6 wherein the degree of polymerization of the condensate is from 2 to 10 units. 8. The element as claimed in claim 6 wherein the degree of polymerization of the condensate is from 2 to 5 units.

9. The element as claimed in claim 6 wherein the concentration of said sensitizing dye in said silver halide emulsion is from 0.002 to 0.2 gram per gram molecule of silver halide and the concentration of said condensate is from 0.1 to 2.0 grams per gram molecule of silver halide.

10. The element as claimed in claim 6 wherein the concentration ratio of said sensitizing dye to said condensate in the silver halide emulsion is from 1:5 to 1:500.

References Cited UNITED STATES PATENTS 2,961,318 11/1960 Jones 96-123 3,043,697 7/1962 Forsgard 96-107 3,342,606 9/1967 Silver 96114 3,501,307 3/1970 Illingsworth 96-101 3,505,070 4/1970 Litzerman et a1. 96101 J. TRAVIS BROWN, Primary Examiner US. Cl. X.R. 96127 

